Citrus juice extraction on a commercial scale can be advantageously performed with a juice extractor including upper and lower cups that move relative to one another along a reciprocal path of travel. The sides of both the upper and lower cups typically comprise fingers that support a fruit so that it can be squeezed without bursting. The fingers of the upper cup interdigitate or intermesh with those of the lower cup.
An orange or other fruit can be fed, for example, to the bottom cup by a cam-operated feeding device. The upper and lower cups are then brought together so that the respective fingers of the cup intermesh and the fruit therebetween is accordingly squeezed.
Sharp, typically circular, cutters are positioned in the top and bottom cups. As the cups move relative to one another, the fruit is pressed against the cutters. The cutters cut plugs from both the top and bottom portions of the fruit as the interdigitating fingers of the two cups mesh together.
The cutting of the plug from the top portion of the fruit promotes separation of the peel from the internal portions of the fruit (i.e., juice and pulp). The plug cut from the lower portion of the fruit allows the internal portions of the fruit to be forced down into a strainer tube positioned just below the lower cup cutter. The strainer tube, in turn, is positioned within a manifold.
After the internal portions of the fruit have been squeezed into the strainer tube, an orifice tube moves upward into the strainer tube applying pressure to the internal portion of the fruit therein. This causes the juice and juice sacs, due to their small particle size, to flow through small holes of the strainer tube and into the juice manifold, thus separating out the juice and pulp. Core material that typically includes membrane, seeds, and peel plugs is discharged out of the bottom of the orifice tube. Such extractors are disclosed, for example, in U.S. Pat. Nos. 5,970,861 and 5,992,311 to Suter et al.
Owing to economic efficiency considerations, the juice extractor should accomplish juice extraction rapidly with a high yield rate (i.e., the quantity of juice recovered relative to the amount of fruit processed). Quality considerations, though, dictate that care should be taken regarding the peel oil extracted from the peel during cutting and squeezing. Such oil, if mixed into the juice in higher quantities, reduces the quality of the juice.
U.S. Pat. No. 5,070,778 to Cross et al. discloses a cutting head comprising a core and a cylindrical blade portion surrounding the core in a spaced relation thereto. Side openings or windows are formed in the side surface of the cylindrical blade portion, and the core has a conical shape adjacent the windows. Accordingly, pressure from the orifice tube pushes some peel oil out the sides of the cutting head through the windows. Rings of fruit peel resulting from cutting plugs in the fruit nonetheless may be mixed in with the internal portions of the fruit. If so, the result is an increase in peel oil in the juice ultimately produced, and, accordingly, a reduction in the quality of the juice.
Successful juice extraction involves a trade-off between high yield rates and high juice quality. With respect to the latter, for example, the amount of peel oil that is introduced into the juice during extraction should be limited.
Another approach to enhancing yield and quality performance was attempted by FMC and included different sized components for the extractor. In particular, typical FMC juice extractors are available in so-called “one inch” and “three-quarter inch” versions. The measurement is the nominal dimension for the inner diameter of the lower cylindrical cutter. The upper cutter is sized slightly larger than the lower cutter. The peel clearance, that is, the space between the outer diameter of the upper cutter and adjacent upper cup portions, is typically the same for either one inch or three-quarter inch components, and is based upon the fruit. In an attempt to produce higher quality juice while still providing high yield, a seven-eighths inch lower cutter was made and used along with a standard sized upper cup for one inch extractor components. Accordingly, to provide the proper peel clearance, the wall thickness of the upper cutter was enlarged to about 0.094 inches. The thick-walled upper cutter also required a larger bore on the lower cup to provide adequate clearance. Unfortunately, even this attempted arrangement of components was not fully satisfactory in meeting juice quality and yield goals.